Auto focus camera, lens apparatus and camera system with a vibration motor drive

ABSTRACT

A camera comprising the following components is disclosed: a vibrating motor which drives a focus lens of an image-taking optical system, and a control circuit which controls the vibrating type motor to repeatedly drive and stop the focus lens, extracting higher frequency components from an image signal obtained from an image pickup device in each stopped state of the focus lens, and performing focus adjusting operation in accordance with a focus adjustment state of the image-taking optical system determined on the basis of the higher frequency components. The control circuit causes traveling wave vibration to be generated on the vibrating member of the vibrating type motor when the focus lens is driven and causes standing wave vibration to be generated on the vibrating member while the focus lens is stopped during the focus adjusting operation.

The present application is a divisional of U.S. application Ser. No.10/189,073 now U.S. Pat. No. 7,133,077, filed Jul. 2, 2002, the contentsof which is hereby incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a camera, a lens apparatus, and acamera system which are provided with an autofocus mechanism, and moreparticularly, to those which use a vibrating type motor to drivefocusing in an image-taking optical system.

2. Description of the Related Art

A vibrating type motor, also referred to as an vibration wave motor orthe like, produces output in such a manner that two-phase cycle signalswith different phases are applied to electromechanical energy conversionelements (electrostrictive elements) provided for a vibrating member tocause the vibrating member to vibrate in a traveling wave (that is, togenerate a traveling vibration wave on a surface of the vibratingmember), thereby driving a moving (driven) member in press contact withthe vibrating member by friction. In the vibrating type motor, thevibrating member is made non-vibrating to hold the position of themoving member by a frictional force acting between the vibrating memberand the moving member.

Since such a vibrating type motor is characterized by high torque at lowrotational speed, driving noise hardly produced, favorableresponsiveness and the ability to accurately control positions, it isused for autofocus drive in cameras, interchangeable lenses or the like.

For autofocus (AF) schemes of cameras or the like, an AF systememploying a phase difference detection scheme is used in many models ofcameras of a so-called single-lens reflex camera type in which imagesare taken on silver films. The AF system of the phase differencedetection scheme operates as follows.

As shown in FIG. 12, light flux incident through an image-taking lens isreflected to a lower portion of a camera by a sub-mirror 502 attached tothe back of a semi-transparent main mirror 501 disposed at an angle of45 degrees to an image-taking optical axis L. The reflected light fluxpasses through an infrared cutting filter 504, and is divided into twoparts by a field lens 503 of a secondary optical system. The two partsof light flux form two images on a pair of AF sensors in an AF sensorunit 505 through a secondary imaging lens 508.

The paired AF sensors 506, 507 are disposed side by side and produceoutputs as shown in FIG. 13. A difference in spacing between the outputsfrom the two images formed on the paired AF sensors 506, 507 is reliedon to determine an in-focus, a front-focus, or a back-focus state.Focusing is achieved by moving a focus lens such that the spacingbetween the outputs of the images matches the spacing in the in-focusstate.

The amount of the movement of the focus lens, that is, the amount ofmovement of an image surface, is determined by calculation from thespacing between the outputs of the two images with the followingalgorithm.

First, the outputs from the two AF sensors 506, 507 are acquired asdata, and the correlation is examined between the outputs from the twosensors 506, 507. The correlation is determined with “the MIN algorithm”in which a correlation U0 is calculated as:

${U\; 0} = {\sum\limits_{j}^{m}{\min\left( {{A\lbrack j\rbrack},{B\lbrack j\rbrack}} \right)}}$

-   -   (min(a,b) refers to a smaller one of a and b) where data from        the sensor 1 (506) is represented by A[1]-A[n] and data from the        sensor 2 (507) is represented by B[1]-B[n].

After the calculation of the U0, a correlation U1 is calculated betweendata on an image A shifted by one bit in the AF sensor and the data onan image B as shown in FIG. 14. The U1 is represented as:

${U\; 1} = {\sum\limits_{j}^{m}{\min\left( {{A\left\lbrack {j + 1} \right\rbrack},{B\lbrack j\rbrack}} \right)}}$

Correlations are successively calculated from images shifted on abit-by-bit basis. The correlation is at a maximum value when two imagesmatch, and the amount of shift at the maximum value is found. From datain the neighborhood of the value, a true maximum value of thecorrelation is obtained by interpolation. The amount of shift at thetrue maximum value is considered as an amount of displacement.

Since an optical system has a unique relationship between the amount ofdisplacement and the amount of movement of an image surface, that is, aso-called defocus amount, the amount of defocus is determined from theamount of displacement. An amount of movement of the focus lens is foundfrom the defocus amount, and the lens is moved to achieve focusing.

As described above, the AF of the phase difference detection schemedetects a defocus amount for a subject, so that it is possible todetermine in which direction the focus lens should be driven by whatamount to achieve focusing by calculations based on the detected defocusamount. Thus, achieving focusing requires lens driving only once, andfast, quiet and accurate AF control can be performed while thecharacteristics of the vibrating type motor are made use of. For thisreason, a number of commercially manufactured cameras or interchangeablelenses are equipped with the phase difference scheme AF and thevibrating type motor.

On the other hand, in a digital camera which acquires images by atwo-dimensional image pickup device and electrically records an imagesignal on a recording medium, an AF scheme referred to as a contrastdetection scheme is employed.

The contrast detection scheme AF generally operates as follows. Theconfiguration thereof has an image-taking system including atwo-dimensional image pickup device, a system control section includinga calculation circuit and a circuit for producing a control signal fordriving a focus lens, and a lens section including a lens controlcircuit for moving the focus lens in an optical axis direction.

The image-taking system admits image light, and outputs and sends it asan image signal to the system control section which in turn extractshigher frequency components included in the image signal. The maximumvalue of the extracted signal is stored. The focus lens is moved by acertain amount in a certain direction. Then, image light is againadmitted and higher frequency components are extracted.

When the maximum value of the extracted signal is larger than thepreviously stored value, the focus lens is considered as moving towardan in-focus position. The current value is newly stored and the focuslens is moved in the same direction.

When the current maximum value of the extracted signal is smaller thanthe previous one, the focus lens is considered as moving away from thein-focus position. The current value is newly stored and the focus lensis moved by a certain amount in a direction opposite to the previousmoving direction. Then, image light is again admitted, higher frequencycomponents are extracted, and the maximum value is compared with thenewly stored one. The image surface is finally caused to reach thein-focus position.

Description is made with reference to FIG. 15. The horizontal axis ofthe graph in FIG. 15 represents the position of an image surface and thevertical axis represents the maximum value of higher frequencycomponents. A point a indicates the position of an image surface at astarting point and a point b indicates the in-focus plane. The maximumvalue of higher frequency components at the point a is assumed as “A.”The focus lens is then moved to the right in the graph, that is, in adirection toward the in-focus plane. The maximum value of higherfrequency components at a point a′ after the movement is “A′” and acomparison between them shows that A′ is larger than A. The focus lensis thus continuously moved in the same direction.

After several comparisons, A is larger than A″ (A″ is the maximum valueat a point a″) at an image surface position past the point b, and it ispossible to determine that the focus lens is now moving in a directionaway from the in-focus plane. Thus, the moving direction of the focuslens is reversed to match the image surface to the in-focus plane.

As described above, since the contrast detection scheme AF involvesmovement of the lens toward the in-focus position while searches aremade for the lens position where higher frequency components of theimage obtained from the image signal are at maximum, image signals needto be acquired with the position of the focus lens being movedgradually. Thus, the lens driving requires repeated driving over a shortdistance. To reduce a time taken for achieving focus, the repeateddriving and stop of the focus lens must be performed quickly.

When the aforementioned contrast detection scheme AF is used in adigital camera, it is necessary to perform driving of a focus adjustinglens by a small amount and AF operation a number of times to bring thefocus adjusting lens near the in-focus point if an image-taking lens hasa large focal length and an image on an image pickup device issignificantly blurred, which presents a problem of a long time taken forthe focusing operation.

In contrast, the phase difference detection scheme AF does not presentsuch a problem since focus can be substantially achieved by one-timelens driving.

On the other hand, a digital camera has an image pickup devicesignificantly smaller in size than a silver film and thus requires ahigher resolution for AF detection corresponding to the radio of thesizes. The phase difference detection scheme AF, however, has a problemthat this requirement cannot be satisfied due to the limitation on thesize of the secondary imaging lens 508 shown in FIG. 12.

In view of such problems, a so-called hybrid scheme AF has been proposedin which the phase difference detection scheme is first used to performfocusing operation of a focus adjusting lens at low resolution and thenthe contrast detection scheme is used to perform fine adjustment of thefocusing operation.

The vibrating type motor, however, is not sufficiently excellent inresponsiveness upon actuation for performing the contrast detectionscheme AF which requires quickly repeated driving and stop although thevibrating type motor has the characteristic of high responsiveness tosome extent. A long time may be needed before focus is achieved in thecontrast detection scheme AF.

In the vibrating type motor, the vibrating member is in strongfrictional contact with the moving member, and the frictional contact isused to transfer a driving force. Thus, to move the moving member in atraveling vibration wave at the time of start of driving, a large forceexceeding the static friction force during stop of the moving member isrequired, which causes insufficient responsiveness upon actuation.

To address this, proposals for improving the responsiveness uponactuation have been made in which the vibrating member of the vibratingtype motor is provided with vibrating energy before the start of drivingwith a traveling vibration wave by causing the electromechanical energyconversion elements to produce a standing vibration wave and then atraveling vibration wave.

Among the proposals, Japanese Patent Application Laid-Open No. 8-80073proposes a method of driving a vibrating type motor in a standing waveswitched from traveling wave driving for a certain time period after anin-focus state is reached.

In the contrast detection scheme AF, however, the remaining drivingamount cannot be calculated due to its characteristic that the in-focusposition is searched for while the lens is driven little by little asdescribed above, and thus the technique in the aforementioned proposalcannot be employed. In addition, the aforementioned proposal attempts,after completion of focus adjusting operation of a focus lens (afterfocusing is achieved), to improve startup characteristics of the nextfocus adjusting operation, and does not attempt to reduce a time takenfor operation before focus is achieved.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a camera, a lensapparatus, and a camera system which allow a reduction in time taken forachieving focusing when the contrast detection scheme AF is performed byusing a vibrating type motor.

To achieve the aforementioned object, a camera according to the presentinvention comprises:

an image-taking optical system which forms an optical image by luminousflux from a subject and includes a focus lens;

an image pickup device which photoelectrically converts the opticalimage formed by the image-taking optical system to an image signal andoutputs the image signal;

a vibrating type motor which drives the focus lens, the vibrating typemotor including a vibrating member, an electro-mechanical energyconversion element which excites vibration on the vibrating member, anda driven member driven by the vibration of the vibrating member; and

a control circuit which controls the vibrating type motor to repeatedlydrive and stop the focus lens, extracts higher frequency components fromthe image signal obtained from the image pickup device in each stoppedstate of the focus lens, and performs focus adjusting operation ofmoving the focus lens to an in-focus position in accordance with a focusadjustment state of the image-taking optical system determined on thebasis of the higher frequency components.

The control circuit causes traveling wave vibration to be generated onthe vibrating member of the vibrating type motor when the focus lens isdriven and causes standing wave vibration to be generated on thevibrating member while the focus lens is stopped during the focusadjusting operation.

To achieve the aforementioned object, a lens apparatus according to thepresent invention has an image-taking optical system which forms anoptical image by luminous flux from a subject and includes a focus lens,and a vibrating type motor which drives the focus lens, the vibratingtype motor including a vibrating member, an electro-mechanical energyconversion element which excites vibration on the vibrating member, anda driven member driven by the vibration of the vibrating member,

the lens apparatus is removably mounted on a camera having an imagepickup device which photoelectrically converts the optical image to animage signal and outputs the image signal, the camera extracting higherfrequency components from the image signal obtained from the imagepickup device in each stopped state of the focus lens and outputting acommand signal for performing focus adjusting operation in accordancewith a determination result of a focus adjustment state of theimage-taking optical system determined on the basis of the higherfrequency components.

The lens apparatus comprises:

a communication circuit which transmits and receives a signal to andfrom the camera; and

a control circuit which controls the vibrating type motor to repeatedlydrive and stop the focus lens and performs focus adjusting operation ofmoving the focus lens to an in-focus position in response to the commandsignal received from the camera through the communication circuit.

The control circuit causes traveling wave vibration to be generated onthe vibrating member of the vibrating type motor when the focus lens isdriven and causes standing wave vibration to be generated on thevibrating member while the focus lens is stopped during the focusadjusting operation.

Further, to achieve the aforementioned object, a camera system accordingto the present invention includes a lens apparatus having animage-taking optical system which forms an optical image by luminousflux from a subject and includes a focus lens, and a vibrating typemotor which drives the focus lens, the vibrating type motor including avibrating member, an electro-mechanical energy conversion element whichexcites vibration on the vibrating member, and a driven member driven bythe vibration of the vibrating member, and

a camera on which the lens apparatus is removably mounted, the camerahaving an image pickup device which photoelectrically converts theoptical image to an image signal and outputs the image signal, thecamera extracting higher frequency components from the image signalobtained from the image pickup device in each stopped state of the focuslens and outputting a command signal for performing focus adjustingoperation in accordance with a focus adjustment state of theimage-taking optical system determined on the basis of the higherfrequency components.

The camera system comprises:

a communication circuit which transmits and receives a signal betweenthe lens apparatus and the camera; and

a control circuit provided for the lens apparatus which controls thevibrating type motor to repeatedly drive and stop the focus lens andperforms focus adjusting operation of moving the focus lens to anin-focus position in response to the command signal received from thecamera through the communication circuit.

The control circuit causes traveling wave vibration to be generated onthe vibrating member of the vibrating type motor when the focus lens isdriven and causes standing wave vibration to be generated on thevibrating member while the focus lens is stopped during the focusadjusting operation.

Further, to achieve the aforementioned object, a camera according to thepresent invention comprises:

an image-taking optical system which forms an optical image by luminousflux from a subject and includes a focus lens;

a first focus detection unit which detects a focus adjustment state ofthe image-taking optical system in a phase difference detection schemeby using luminous flux from the image-taking optical system;

an image pickup device which photoelectrically converts the opticalimage formed by the image-taking optical system to an image signal andoutputs the image signal;

a second focus detection unit which detects a focus adjustment state ofthe image-taking optical system in a contrast detection scheme based onthe image signal from the image pickup device;

a vibrating type motor which drives the focus lens, the vibrating typemotor including a vibrating member, an electromechanical energyconversion element which excites vibration on the vibrating member, anda driven member driven by the vibration of the vibrating member; and

a control circuit which controls the vibrating type motor based on thedetection results of the first and second focus detection units.

The control circuit performs first-stage driving control for generatingtraveling wave vibration on the vibrating member of the vibrating typemotor based on the detection result of the first focus detection unit,then performs second-stage driving control for generating traveling wavevibration on the vibrating member based on the detection result of thesecond focus detection unit, and performs intermediate control forgenerating standing wave vibration on the vibrating member from aftercompletion of the first-stage driving control until start of thesecond-stage driving control.

Furthermore, to achieve the aforementioned object, a lens apparatusaccording to the present invention has an image-taking optical systemwhich forms an optical image by luminous flux from a subject andincludes a focus lens, and a vibrating type motor which drives the focuslens, the vibrating type motor including a vibrating member, anelectromechanical energy conversion element which excites vibration onthe vibrating member, and a driven member driven by the vibration of thevibrating member,

the lens apparatus is removably mounted on a camera, the camera having afirst focus detection unit which detects a focus adjustment state of theimage-taking optical system in a phase difference detection scheme byusing luminous flux from the image-taking optical system, an imagepickup device which photoelectrically converts the optical image formedby the image-taking optical system to an image signal and outputs theimage signal, and a second focus detection unit which detects a focusadjustment state of the image-taking optical system in a contrastdetection scheme based on the image signal from the image pickup device,and the camera outputting a command signal for performing focusadjusting operation based on signals from the first and second focusdetection units.

The lens apparatus comprises:

a communication circuit which transmits and receives a signal to andfrom the camera; and

a control circuit which controls the vibrating type motor in response tothe command signal received from the camera through the communicationcircuit.

The control circuit performs first-stage driving control for generatingtraveling wave vibration on the vibrating member of the vibrating typemotor based on the detection result of the first focus detection unit,then performs second-stage driving control for generating traveling wavevibration on the vibrating member based on the detection result of thesecond focus detection unit, and performs intermediate control forgenerating standing wave vibration on the vibrating member from aftercompletion of the first-stage driving control until start of thesecond-stage driving control.

Furthermore, to achieve the aforementioned object, a camera systemaccording to the present invention including a lens apparatus, the lensapparatus having an image-taking optical system which forms an opticalimage by luminous flux from a subject and includes a focus lens, and avibrating type motor which drives the focus lens, the vibrating typemotor including a vibrating member, an electromechanical energyconversion element which excites vibration on the vibrating member, anda driven member driven by the vibration of the vibrating member, and

a camera having a first focus detection unit which detects a focusadjustment state of the image-taking optical system in a phasedifference detection scheme by using luminous flux from the image-takingoptical system, an image pickup device which photoelectrically convertsthe optical image formed by the image-taking optical system to an imagesignal and outputs the image signal, and a second focus detection unitwhich detects a focus adjustment state of the image-taking opticalsystem in a contrast detection scheme based on the image signal from theimage pickup device, and the camera outputting a command signal forperforming focus adjusting operation based on signals from the first andsecond focus detection units.

The camera system comprises:

a communication circuit which transmits and receives a signal betweenthe camera and the lens apparatus; and

a control circuit provided for the lens apparatus which controls thevibrating type motor in response to the command signal received throughthe communication circuit.

The control circuit performs first-stage driving control for generatingtraveling wave vibration on the vibrating member of the vibrating typemotor based on the detection result of the first focus detection unit,then performs second-stage driving control for generating traveling wavevibration on the vibrating member based on the detection result of thesecond focus detection unit, and performs intermediate control forgenerating standing wave vibration on the vibrating member from aftercompletion of the first-stage driving control until start of thesecond-stage driving control.

A detailed configuration of the camera, lens apparatus and camera systemof the invention, the above and other objects and features of theinvention will be apparent from the embodiments, described below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing the configuration of a digital cameraof a type containing an image-taking lens which is an embodiment of thepresent invention;

FIG. 2 is a flow chart showing an AF sequence in a contrast detectionscheme in the camera of the embodiment shown in FIG. 1;

FIG. 3 is a block diagram showing the configuration of aninterchangeable lens apparatus which is another embodiment of thepresent invention;

FIGS. 4(A) and (B) show a flow chart showing an AF sequence in theinterchangeable lens apparatus of the embodiment shown in FIG. 3;

FIG. 5 is a block diagram showing the configuration of a digital camerasystem which is another embodiment of the present invention;

FIG. 6 is a flow chart showing an AF sequence in the contrast detectionscheme of a camera forming part of the camera system of the embodimentshown in FIG. 5;

FIG. 7 is a flow chart showing an AF sequence in the contrast detectionscheme of an interchangeable lens apparatus forming part of the camerasystem of the embodiment shown in FIG. 5;

FIG. 8 is a block diagram showing the configuration of a digital camerawhich is another embodiment of the present invention;

FIGS. 9(A) and (B) show a flow chart showing control of focusingoperation in the digital camera of the embodiment shown in FIG. 8;

FIG. 10 is a block diagram showing the configuration of a digital camerasystem which is another embodiment of the present invention;

FIGS. 11(A) and (B) show a flow chart showing control of focusingoperation in the digital camera system of the embodiment shown in FIG.10;

FIG. 12 shows the schematic configuration of an optical system for AF ina phase difference detection scheme;

FIG. 13 shows an AF sensor and its output in phase difference detectionscheme AF;

FIG. 14 shows plots for explaining calculations of correlation (MINalgorithm) between two images in the phase difference detection schemeAF;

FIG. 15 is a chart showing the relationship between the position of alens image surface and higher frequency components extracted from animage signal in the contrast detection scheme AF;

FIG. 16 shows the arrangement of electrodes and electrostrictiveelements attached to a stator (vibrating member) of a vibrating typemotor for use in the aforementioned respective embodiments; and

FIG. 17 is a plot showing the relationship among the frequency of adriving signal applied to the stator of the aforementioned vibratingtype motor, a phase difference, and the number of revolutions.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, preferred embodiments of the invention will be described indetail with reference to the drawings.

FIG. 1 shows the configuration of a digital camera of a type containingan image-taking lens which is an embodiment of the present invention.

In FIG. 1, reference numeral 1 shows the digital camera (hereinaftersimply referred to as a camera). In an image-taking system, referencenumeral 2 shows a focus lens which performs focus adjustment, 3 a zoomlens which adjusts a magnification, 4 a stop which adjusts an amount oflight, 6 an image pickup device such as a CCD and a CMOS whichphotoelectrically converts image light to an image signal for output,and 5 a shutter which adjusts an amount of light to the image pickupdevice 6.

Reference numeral 7 shows an A/D converter which digitizes an imagesignal from the image pickup device 6, 8 an electrical viewfinder systemwhich displays an image picked up by the image pickup device 6, 9 adigital signal processing section which performs various digital signalprocessing of a digital image signal converted by the A/D converter 7,10 a buffer memory used to temporarily store the digital image signal orthe like, and 11 a recording medium such as a flash memory or othersemiconductor memory, magnetic disk, optical disk, etc. which recordstaken digital data.

Reference numeral 12 shows an external LCD display system which displaysvarious information such as an image-taking mode and the number of takenimages, and 13 a camera CPU (control circuit) which performs control ofthe overall camera 1.

Reference numeral 14 shows a stop driving motor, 15 a vibrating typemotor which drives the focus lens 2, 16 a driver circuit which drivesthe vibrating type motor 15, and 17 a driver circuit which drives thestop driving motor 14. The camera 1 has a power battery, not shown,mounted therein.

The vibrating type motor 15 is now described with reference to FIG. 16.FIG. 16 shows the arrangement of electrostrictive elements disposed on astator (vibrating member) formed of an elastic member such as materialetc., in the vibrating type motor 15.

A and B in FIG. 16 show first and second electrostrictive elementgroups, respectively, disposed on the stator to have phases andpolarization as shown. S indicates a sensor electrostrictive elementdisposed at a position shifted in phase 45 degrees to the firstelectrostrictive element group B. These electrostrictive elements may berealized by attaching separate ones on the stator or by polarizing anintegral electrostrictive element.

In FIG. 16, A1, B1 show driving electrodes for the first and secondelectrostrictive element groups A, B, respectively. A cycle voltage isapplied to the electrode A1 and a cycle voltage with a different phasewith the cycle voltage applied to the electrode A1 is applied to theelectrode B1 to form a traveling vibration wave on the surface of thestator.

S1 shows a sensor electrode for the sensor electrostrictive element S.When a vibration wave is formed on the surface of the stator, a cyclevoltage is output from the sensor electrostrictive element S inaccordance with the vibration state of the vibration wave. The cyclevoltage is taken from the sensor electrode S1 to enable detection of thevibration state of the stator.

The vibrating type motor has a characteristic that a specific phaserelationship is observed at resonance between the driving voltage to thedriving electrode A1 and the output voltage from the sensor electrodeS1. The relationship is determined by the positional relationshipbetween the first electrostrictive element group A to which the cyclesignal is applied through the driving electrode A1 and the sensorelectrostrictive element S.

In the case of the embodiment, the resonance occurs when the signalwaveforms to the electrode A1 and from the electrode S1 have a phaseshift of 135 degrees in normal rotation, while the resonance occurs whenthe signal waveforms have a phase shift of 45 degrees in reverserotation. The phase difference is larger as a deviation from theresonance is greater.

FIG. 17 shows the phase characteristic between the phase A and phase Sof the vibrating type motor, in which the horizontal axis represents adriving frequency f, a vertical axis 1 a phase difference θ between thephase A and phase S, and a vertical axis 2 the number of revolutions n.

In FIG. 17, the phase difference θ between the phase A and phase S issmaller toward the top, the number of revolutions n is higher toward thetop, and the frequency f is higher toward the right.

The vibrating type motor has a higher number of revolutions n and asmaller phase difference θ between the phase A and phase S as thedriving frequency f is scanned from high to low levels. However, as thedriving frequency f is reduced past the resonance frequency f0, thenumber of revolutions is suddenly reduced and the phase difference θ isalso changed quickly. The characteristic depends on temperature or load,and especially when load is increased, a shift occurs in a directionindicated by an arrow in FIG. 17 (in which the frequency is higher).

Next, description is made with reference to FIG. 2 for an operationsequence of the camera CPU 13 in the contrast detection scheme AFemployed in the aforementioned camera 1. However, the sequence in FIG. 2is an example of the contrast detection scheme AF, and another sequencemay be performed in the contrast detection scheme AF for driving thevibrating type motor to generate a standing wave.

[Step 101]

The sequence is started in response to turn-on of a main switch, notshown, of the camera 1.

[Step 102]

The camera CPU 13 determines whether or not a release button, not shown,provided for the camera 1 is half-pressed to make a SW1 ON. If the SW1is ON, the sequence proceeds to step 103. If the SW is OFF, a standbystate is entered.

[Step 103]

In response to the turn-on of the SW1, an image signal output from theimage pickup device 6 is acquired.

[Step 104]

Higher frequency components are extracted from the image signal acquiredat step 103.

[Step 105]

The data on the higher frequency components extracted at step S104 istemporarily stored in the memory buffer 10.

[Step 106]

The focus lens 2 is driven by a certain amount. While the driving amountis always constant (for example, a minute driving amount) in theembodiment, the driving amount may be changed in accordance with thenewest value of the higher frequency component data. For example, whenthe value of the higher frequency component data is small, the focuslens 2 is considered as being at some distance from an in-focus positionand the driving amount is increased, and when the value of the higherfrequency component data is large, the focus lens 2 is considered asbeing near the in-focus position and the driving amount is reduced.

The driving of the focus lens 2 is now described. When the sequenceproceeds to step S106 from step S105, the vibrating type motor is at acomplete standstill (the stator is non-vibrating). Thus, high frequencydriving signals (cycle signals for the phases A and B) are applied tothe electrostrictive elements of the vibrating type motor 15 to causethe stator to generate traveling wave vibration, and the vibrating typemotor 15 is actuated and driven by the certain amount with the frequencybeing gradually reduced. In this event, the phase difference between thephase A and phase S described above is read to perform control such thatthe driving frequency does not fall below the resonance frequency f0.

As a target position after driving by the certain amount is approached,the frequency of the driving signals for the phases A, B is increased todecelerate the driving of the vibrating type motor 15. After the drivingby the certain amount, the driving signals for the phases A, B to thevibrating type motor 15 are switched from a phase difference forgenerating traveling wave vibration to a phase difference for generatingstanding wave vibration to stop (temporarily stop) the focus lens 2(step 107). The driving frequency when the traveling wave vibration isswitched to the standing wave vibration is a startup frequency (theaforementioned high frequency) used for starting to actuate thevibrating type motor 15 by the traveling wave vibration.

When the sequence proceeds to step S106 from step S112, the stator ofthe vibrating type motor 15 is vibrating in a standing wave and thevibrating type motor 15 is not driven. The driving signals for thephases A, B are switched from the phase difference for generatingstanding wave vibration to the phase difference for generating travelingwave vibration to drive the vibrating type motor 15 by the certainamount. In this event, the phase difference between the phase A andphase S described above is also read to perform control such that thedriving frequency does not fall below the resonance frequency f0. Afterthe driving by the certain amount, the driving signals for the phases A,B are switched from the phase difference for generating traveling wavevibration to the phase difference for generating standing wave vibrationto stop the focus lens 2 (step 107).

The traveling wave vibration of the stator is generated by applyingdriving signals for the phases A, B having a phase difference of 90degrees to the electrode Al and the electrode B1 shown in FIG. 16. Thedriving direction may be switched by advancing or delaying the phase ofthe signal applied to the electrode B1 with respect to the signalapplied to the electrode A1.

The standing wave vibration of the stator can be generated by applying adriving signal to one of the electrode A1 and the electrode B1 orapplying driving signals with the same phases to the electrodes A1, B1.Driving signals with a phase difference of 180 degrees may be applied tothe electrodes A1, B1. The driving frequency in the standing wavevibration is the startup frequency (the aforementioned high frequency)used for actuating the vibrating type motor 15 by the traveling wavevibration.

[Step 107]

After the focus lens 2 is driven by the certain amount in this manner,an image signal output from the image pickup device 6 is again acquiredwhile the vibrating type motor 15 is in the standing wave driving state.

[Step 108]

Higher frequency components are extracted from the image signal acquiredat step 107.

[Step 109]

The previously extracted higher frequency component data is comparedwith the higher frequency component data extracted this time at step108.

If the previously extracted data shows a larger value, the drivingdirection at step 106 is considered as opposite to the in-focus positionand the sequence proceeds to step 110, or otherwise, the drivingdirection at step 106 is considered as leading to the in-focus positionand the sequence proceeds to step 111.

[Step 110]

Since the in-focus position is opposite to the driving direction, thecamera CPU 13 makes setting to reverse the direction in the next drivingof the focus lens 2.

[Step 111]

Since the driving direction leads to the in-focus position, the higherfrequency component data extracted at step 108 is temporarily stored inthe buffer memory 10.

[Step 112]

Whether or not focusing (in-focus state) is achieved is determined fromthe value of the higher frequency component data stored in the memorybuffer 10, the condition whether or not the focus lens 2 is reverselydriven near the current position of the focus lens 2, and the like. Ifit is determined that focusing is achieved, the sequence proceeds tostep 113. If it is determined that focusing is not achieved, thesequence returns to step 106 at which the focus lens 2 is again drivenby the certain amount and then driven in the standing wave(temporarilystopped), and an image signal is again acquired.

In this manner, the vibrating type motor 15 (focus lens 2) is repeatedlydriven and stopped until it is determined that focusing is achieved, inother words, until the focus lens 2 is moved to a position where thehigher frequency component data reaches a maximum value.

[Step 113]

If it is determined that focusing is achieved at step 112, the vibratingtype motor 15 or the focus lens 2 is stopped. In this event, thevibrating type motor 15, which has generated the standing wavevibration, is made non-vibrating and completely stopped by stopping theapplication of the driving signal.

This is performed for the following reason. Since the moving member(driven member, for example rotor) is in a kind of floating state to thestator while the vibrating type motor 15 generates the standing wavevibration, and the focus lens 2 is readily moved by a small externalforce, the vibrating type motor 15 is made non-vibrating and completelystopped to hold the in-focus position. The stop of the application ofthe driving signal to the vibrating type motor 15 also has the effect ofpower savings. Then, the sequence is ended (step 114).

In the embodiment, the vibrating type motor 15 is caused to vibrate inthe standing wave each time the focus lens 2 is temporarily stoppedafter driving by the certain amount during the focusing operation untilfocusing is achieved in the operation of the contrast detection schemeAF. Alternatively, it is possible that a time period until the focuslens 2 is moved to within a predetermined range (near the in-focusposition) including the in-focus position is set as a first mode, a timeperiod until the focus lens 2 is moved to the in-focus position in thatpredetermined range is set as a second mode, and the vibrating typemotor 15 is caused to generate the standing wave vibration and not to bedriven only at the time of temporary stop when the lens is repeatedlydriven by a small amount in the second mode.

FIG. 3 shows the configuration of an interchangeable lens apparatuswhich is another embodiment of the present invention. In FIG. 3,reference numeral 18 shows the interchangeable lens apparatus, andreference numeral 40 shows a camera on which the interchangeable lensapparatus 18 is removably mounted (hereinafter simply referred to as acamera). The camera 40 may support the contrast detection scheme AF orAF in a scheme other than the contrast detection scheme (for example,the phase difference detection scheme).

In an image-taking optical system in the interchangeable lens apparatus18, reference numeral 19 shows a focus lens which performs focusadjustment, 20 a zoom lens which adjusts a magnification, and 21 a stopwhich adjusts an amount of light.

Reference numeral 23 shows a stop driving motor, 22 a vibrating typemotor which drives the focus lens 19, 24 a driver circuit which drivesthe vibrating type motor 22, and 25 a driver circuit which drives thestop driving motor 22. Reference numeral 27 shows a lens CPU (controlcircuit) which controls the lens apparatus 18, and 26 a communicationinterface which allows communication between the lens CPU 27 and acamera CPU 47, later described.

The camera 40 is provided with an image pickup device or a silver film,not shown, and a shutter which adjusts an amount of light to the imagepickup device or film. The camera CPU 47 controls the overall camera.Reference numeral 48 shows a communication interface which allowscommunication between the camera CPU 47 and the lens CPU 27. The camera40 has a power battery, not shown, mounted therein, and the lensapparatus 18 is supplied with power from the camera 40.

In the embodiment, the camera CPU 47 transmits a command for driving thefocus lens 19 to the lens CPU 27 which controls the vibrating type motor22 in accordance with the AF scheme employed in the camera 40. Theprocessing of the lens CPU 27 is hereinafter described by using FIG.4(A) and FIG. 4(B). Lines added circled 1 in FIG. 4(A) and FIG. 4(B) areconnected to each other.

[Step 201]

The sequence is started when the lens apparatus 18 is mounted on thecamera 40.

[Step 202]

The lens CPU 27 performs initial communication with the camera CPU 47through the communication interfaces 26, 48.

[Step 203]

The lens CPU 27 determines whether or not the camera 40 support thecontrast detection scheme AF from the initial communication performed atstep 202. Specifically, information transmitted from the camera duringthe initial communication includes information for identifying the AFscheme, and the AF scheme is identified from that information. Thesequence proceeds to step 204 if the information indicates the contrastdetection scheme, or to step 212 if the information indicates a schemeother than the contrast detection scheme (for example, the phasedifference detection scheme).

[Step 204]

Since the AF scheme supported by the camera 40 is the contrast detectionscheme, a standing wave driving mode is established in which thevibrating type motor 22 is caused to vibrate in a standing wave at thetime of stop during focus operation. The operation in the standing wavedriving mode is described up to step 211.

First, it is determined whether or not the content of the communicationtransmitted from the camera is a focus lens driving instruction (commandsignal), and the sequence proceeds to step 207 if it is the focus lensdriving instruction, or to step 205 if not.

[Step 205]

It is determined whether or not the content of the communicationtransmitted from the camera is a driving stop instruction for the focuslens 19 (end command), and the sequence proceeds to step 206 if it isthe driving stop instruction, or returns to step 204 and the lens CPU 27waits for communication if not.

[Step 206]

Since the content of the communication is determined to be the drivingstop instruction at step 205, the application of a driving signal to thevibrating type motor 22 is stopped, and the vibrating type motor 22 ismade non-vibrating and completely stopped. The driving stop instructionis transmitted when it is determined that focusing (in-focus state) isachieved in the camera 40 or when transition is made to a low powerconsumption mode.

[Step 207]

The lens CPU 27, upon reception of the focus lens driving instruction,determines whether or not the vibrating type motor 22 is vibrating in astanding wave. The sequence proceeds to step 209 if it is vibrating in astanding wave, or to step 208 if it is non-vibrating with no standingwave vibration (at a complete standstill).

[Step 208]

Since the vibrating type motor 22 is now non-vibrating, higher frequencydriving signals (cycle signals for the phases A, B) are applied toelectrostrictive elements of the vibrating type motor 22 to cause astator to generate traveling wave vibration, and the vibrating typemotor 22 is actuated with the frequency being reduced gradually to drivethe focus lens 19 toward a target position corresponding to a positionafter driving by a certain amount included in the focus lens drivinginstruction. At this point, the phase difference between the phase A andphase S is read to perform control such that the driving frequency doesnot fall below the resonance frequency f0.

[Step 209]

Since the vibrating type motor 22 is now vibrating in a standing wave,driving signals for the phases A, B to the vibrating type motor 22 areswitched from the phase difference for generating standing wavevibration to the phase difference for generating traveling wavevibration to actuate the vibrating type motor 22, and the focus lens 19is driven toward the aforementioned target position.

[Step 210]

It is determined whether or not the focus lens 19 reaches the targetposition (whether or not it is driven by the certain amount), and if thetarget position is reached, the sequence proceeds to step 211. If thetarget position is not reached, the vibrating type motor 22 is drivenuntil the target position is reached.

In this event, it is preferable that control is performed such that thedriving amount remaining before the target position is reached ismonitored and deceleration processing is performed at the time when theremaining driving amount becomes equal to or lower than a certain levelto avoid overrun and prevent a user from feeling shock at the time ofstop.

[Step 211]

Since the focus lens 19 reaches the target position (it is driven by thecertain amount), the driving signals for the phases A, B to thevibrating type motor 22 are switched from the phase difference forgenerating traveling wave vibration to the phase difference forgenerating standing wave vibration to stop (temporarily stop) thevibrating type motor 22 and the focus lens 19. The driving frequencywhen the traveling wave vibration is switched to the standing wavevibration is a startup frequency (the aforementioned high frequency)used for starting to actuate the vibrating type motor 22 by thetraveling wave vibration.

Then, the sequence returns to step 204 and the next driving instructiontransmitted from the camera 40 is waited for. During the wait, thevibrating type motor 22 is vibrating in a standing wave. The camera CPU47 extracts higher frequency components in an image signal output froman image pickup device (not shown) provided for taking images ordetecting focus in the camera 40, detects the focus adjustment state ofthe image-taking optical system, and determines whether or not focusingis achieved.

Upon reception of the next driving instruction from the camera 40, thelens CPU 27 switches the driving signals for the phases A, B to thevibrating type motor 22 to the phase difference for generating travelingwave vibration in order to perform the next driving of the focus lens19.

In this manner, the focus lens 19 is repeatedly driven and stopped eachtime a driving instruction is received from the camera 40, while it isdetermined whether or not higher frequency components show the maximumvalue based on comparisons of higher frequency component data extractedfrom image signals output from the image pickup device of the camera 40in the respective stopped states of the focus lens 19 until focusing isfinally achieved.

Next, description is made for a normal driving mode when the camera 40supports an AF scheme other than the contrast detection scheme (forexample, a phase difference detection scheme).

[Step 212]

It is determined whether or not the content of communication transmittedfrom the camera 40 is a focus lens driving instruction, and the sequenceproceeds to step 213 if it is the focus lens driving instruction, or thelens CPU 27 waits for communication from the camera if not.

[Step 213]

Since the vibrating type motor 22 is at a complete standstill, highfrequency driving signals (cycle signals for the phases A, B) areapplied to the electrostrictive elements of the vibrating type motor 22to cause the stator to generate traveling wave vibration, and thevibrating type motor 22 is actuated with the frequency being reducedgradually to drive the focus lens 19 toward a target position calculatedor the like based on the AF scheme in the camera 40. At this point, thephase difference between the phase A and phase S described earlier isread to perform control such that the driving frequency does not fallbelow the resonance frequency f0.

[Step 214]

It is determined whether or not the focus lens 19 reaches the targetposition, and if the target position is reached, the sequence proceedsto step 215. If the target position is not reached, the vibrating typemotor 22 is driven until the target position is reached. In this event,it is preferable that control is performed such that the driving amountremaining before the target position is reached is monitored anddeceleration processing is performed at the time when the remainingdriving amount becomes equal to or lower than a certain level to avoidoverrun and prevent a user from feeling shock at the time of stop.

[Step 215]

When the focus lens 19 reaches the target position, the application ofthe driving signal to the vibrating type motor 22 is stopped to make thevibrating type motor 22 non-vibrating, thereby completely stopping thevibrating type motor 22 and the focus lens 19.

As described above, since the lens apparatus 18 of the embodiment may beused to switch the driving method of the vibrating type motor inaccordance with the AF scheme of the camera on which the lens ismounted, the lens apparatus of the embodiment can be used both in acamera for AF in the contrast detection scheme and in a camera for AF ina scheme other than the contrast detection scheme. Fast and comfortableAF operation can be performed when the lens apparatus is mounted oneither camera.

FIG. 5 shows the configuration of a camera system which is anotherembodiment of the present invention and comprises a digital camera andan interchangeable lens apparatus. In the embodiment, componentsidentical to those in the previous embodiment are designated with thesame reference numerals as those in the previous embodiment.

In FIG. 5, reference numeral 51 shows the interchangeable lens apparatusand reference numeral 58 shows the digital camera (hereinafter simplyreferred to as a camera) on which the lens apparatus 51 is removablymounted.

In an image-taking optical system in the interchangeable lens apparatus51, reference numeral 19 shows a focus lens which performs focusing, 20a zoom lens which adjusts a magnification, and 21 a stop which adjustsan amount of light.

Reference numeral 23 shows a stop driving motor, 22 a vibrating typemotor which drives the focus lens 19, 24 a driver circuit which drivesthe vibrating type motor 22, and 25 a driver circuit which drives thestop driving motor 22.

Reference numeral 57 shows a lens CPU (control circuit) which controlsthe lens apparatus 51, and reference numeral 26 shows a communicationinterface which allows communication between the lens CPU 57 and acamera CPU 37, later described.

In the camera 58, reference numeral 31 shows an image pickup device suchas a CCD and a CMOS which photoelectrically converts image light to animage signal for output, and reference number 30 shows a shutter whichadjusts an amount of light to the image pickup device 31.

Reference numeral 32 shows an A/D converter which digitizes an imagesignal from the image pickup device 31, 29 an electrical viewfindersystem which displays an image picked up by the image pickup device 31,33 a digital signal processing section which performs various digitalsignal processing of a digital image signal converted by the A/Dconverter 32, 34 a buffer memory used to temporarily store the digitalimage signal or the like, and 35 a recording medium such as a flashmemory or other semiconductor memory, magnetic disk, optical disk, etc.which records taken digital data.

Reference numeral 36 shows an external LCD display system which displaysvarious information such as an image-taking mode and the number of takenimages, and 37 the camera CPU which performs control of the overallcamera 58. Reference numeral 38 shows a communication interface whichallows communication between the camera CPU 37 and the lens CPU 57. Thecamera 58 has a power battery, not shown, mounted therein. The lensapparatus 51 is supplied with power from the camera 58.

Next, description is made for an operation sequence of the camera CPU 37and the lens CPU 57 in the contrast detection scheme AF employed in theaforementioned camera system with reference FIGS. 6 and 7. However, thesequence in FIGS. 6 and 7 is an example of the contrast detection schemeAF, and another sequence may be performed in the contrast detectionscheme AF for driving the vibrating type motor to generate a standingwave.

The operation of the camera CPU 37 is described with reference to FIG.6.

[Step 301]

The sequence is started in response to turn-on of a main switch, notshown, of the camera 58.

[Step 302]

The camera CPU 37 determines whether a release button, not shown,provided for the camera 58 is half-pressed to make a SW1 on. When theSW1 is ON, the sequence proceeds to step 303. When the SW1 is OFF, astandby state is entered.

[Step 303]

In response to the turn-on of the SW 1, an image signal output from theimage pickup device 31 is acquired.

[Step 304]

Higher frequency components are extracted from the image signal acquiredat step 303.

[Step 305]

The data on the higher frequency components extracted at step S304 istemporarily stored in the memory buffer 34.

[Step 306]

A focus driving instruction (command signal) is transmitted to the lensapparatus 51 to drive the focus lens 19 by a certain amount. While thedriving amount is always constant (for example, a minute driving amount)in the embodiment, the driving amount may be changed in accordance withthe newest value of the higher frequency component data. For example,when the value of the higher frequency component data is small, thefocus lens 19 is considered as being at some distance from an in-focusposition and the driving amount is increased, and when the value of thehigher frequency component data is large, the focus lens 19 isconsidered as being near the in-focus position and the driving amount isreduced.

[Step 307]

After the focus lens 19 is driven by the certain amount in the lensapparatus 51, an image signal output from the image pickup device 31 isagain acquired.

[Step 308]

Higher frequency components are extracted from the image signal acquiredat step 307.

[Step 309]

The previously extracted higher frequency component data is comparedwith the higher frequency component data extracted this time at step308. If the previously extracted data shows a larger value, the drivingdirection at step 306 is opposite to the in-focus position and thesequence proceeds to step 310, or otherwise, the driving direction atstep 306 is considered as leading to the in-focus position and thesequence proceeds to step 311.

[Step 310]

Since the in-focus position is opposite to the driving direction, thecamera CPU 37 makes setting to reverse the direction in the next drivingof the focus lens 19.

[Step 311]

Since the driving direction leads to the in-focus position, the higherfrequency component data extracted at step 308 is temporarily stored inthe buffer memory 34.

[Step 312]

Whether or not focusing (in-focus state) is achieved is determined fromthe value of the higher frequency component data stored in the memorybuffer 34, the condition whether the focus lens 19 is reversely drivennear the current position of the focus lens 19, and the like.

When it is determined that focusing is achieved, the sequence proceedsto step 313, and when it is determined that focusing is not achieved,the sequence returns to step 306 at which a driving instruction of thefocus lens 19 by a certain amount is again transmitted and an imagesignal is again acquired.

In this manner, the vibrating type motor 22 (focus lens 19) isrepeatedly driven and stopped until it is determined that focusing isachieved, in other words, until the focus lens 19 is moved to a positionwhere the higher frequency component data reaches a maximum value.

[Step 313]

When it is determined that focusing is achieved at step 312, a drivingstop instruction (end command) is transmitted to the lens apparatus 51to completely stop the vibrating type motor 22 and the focus lens 19.Then, the sequence is ended (step 314).

Subsequently, the operation of the lens CPU 57 is described withreference to FIG. 7.

[Step 401]

The lens apparatus 51 is mounted on the camera 58 and power is providedfrom the camera 58 to start this operation sequence.

[Step 402]

The lens CPU 57 determines whether or not communication is made from thecamera, and the sequence proceeds to step 403 if communication is made,or the lens CPU 57 enters a wait state for communication if not.

[Step 403]

It is determined whether or not the content of the communicationtransmitted from the camera 58 is a focus lens driving instruction(command signal). The sequence proceeds to step 407 if it is the focuslens driving instruction, or to step 404 if it is another instruction.

[Step 404]

It is determined whether or not the content of the communicationtransmitted from the camera 58 is a driving stop instruction of thefocus lens 19 (end command). The sequence proceeds to step 405 if it isthe driving stop instruction, or to step 406 if it is anotherinstruction.

[Step 405]

Since the content of the communication is determined to be the drivingstop instruction at step 403, the application of a driving signal to thevibrating type motor 22 is stopped, and the vibrating type motor 22 ismade non-vibrating and completely stopped.

The driving stop instruction is transmitted when it is determined thatfocus is achieved in the camera 58 or when transition is made to a lowpower consumption mode.

It should be noted that the vibrating type motor 22 is madenon-vibrating and completely stopped by stopping the application of thedriving signal even when the vibrating type motor 22 is vibrating in astanding wave.

This is performed for the following reason. Since the moving member(driven member, for example, rotor) is in a kind of floating state tothe stator while the vibrating type motor 22 generates standing wavevibration, and the focus lens 19 is readily moved by a small externalforce, the vibrating type motor 22 is made non-vibrating and completelystopped to hold an in-focus position. The stop of the application of thedriving signal to the vibrating type motor 22 also has the effect ofpower savings.

[Step 406]

Since the content of the communication transmitted from the camera 58 isan instruction other than the focus lens driving signal and the drivingstop instruction, processing is performed according to that otherinstruction and the sequence proceeds to step 402 at which the lens CPU57 enters a wait state for communication.

[Step 407]

The lens CPU 57, upon reception of the focus lens driving instruction,determines whether or not the vibrating type motor 22 is vibrating in astanding wave. The sequence proceeds to step 409 if it is vibrating in astanding wave, or to step 408 if it is not vibrating in a standing wavebut is non-vibrating (at a complete standstill).

[Step 408]

Since the vibrating type motor 22 is now non-vibrating, high frequencydriving signals (cycle signals for the phases A, B) are applied toelectrostrictive elements of the vibrating type motor 22 to cause thestator to generate traveling wave vibration, and the vibrating typemotor 22 is actuated with the frequency being reduced gradually to drivethe focus lens 19 toward a target position corresponding to a positionafter driving by a certain amount included in the focus lens drivinginstruction. At this point, the phase difference between the phase A andphase S is read to perform control such that the driving frequency doesnot fall below the resonance frequency f0.

[Step 409]

Since the vibrating type motor 22 is now vibrating in a standing wave,the driving signals for the phases A, B to the vibrating type motor 22are switched from the phase difference for generating standing wavevibration to the phase difference for generating traveling wavevibration to actuate the vibrating type motor 22, and the focus lens 19is driven toward the aforementioned target position. In this event, thephase difference between the phase A and phase S is also read to performcontrol such that the driving frequency does not fall below theresonance frequency f0.

The traveling wave vibration of the stator is generated by applyingdriving signals for the phases A, B having a phase difference of 90degrees to the electrode A1 and the electrode B1 shown in FIG. 16. Thedriving direction may be switched by advancing or delaying the phase ofthe signal applied to the electrode B1 with respect to the signalapplied to the electrode A1.

The standing wave vibration of the stator can be generated by applying adriving signal to one of the electrode A1 and the electrode B1 orapplying driving signals with the same phase to the electrodes A1, B1.Driving signals with a phase difference of 180 degrees may be applied tothe electrodes A1, B1.

[Step 410]

It is determined whether or not the focus lens 19 reaches the targetposition (whether or not it is driven by the certain amount), and if thetarget position is reached, the sequence proceeds to step 411. If thetarget position is not reached, the vibrating type motor 22 is drivenuntil the target position is reached.

In this event, it is preferable that control is performed such that thedriving amount remaining before the target position is reached ismonitored and deceleration processing is performed at the time when theremaining driving amount becomes equal to or lower than a certain levelto avoid overrun and prevent a user from feeling shock at the time ofstop.

[Step 411]

Since the focus lens 19 reaches the target position, the driving signalsfor the phases A, B to the vibrating type motor 22 are switched from thephase difference for generating traveling wave vibration to the phasedifference for generating standing wave vibration to stop (temporarilystop) the vibrating type motor 22 and the focus lens 19. The drivingfrequency when the traveling wave vibration is switched to the standingwave vibration is a startup frequency (the aforementioned highfrequency) used for starting to actuate the vibrating type motor 22 bythe traveling wave vibration.

Then, the sequence returns to step 402 at which the lens CPU 57 waitsfor the next driving instruction transmitted from the camera 58. Duringthe wait, the vibrating type motor 22 is vibrating in a standing wave.The camera CPU 37 extracts higher frequency components in an imagesignal output from the image pickup device 31, detects the focusadjusting state of the image-taking optical system, and determineswhether or not focusing (in-focus state) is achieved.

Upon reception of the next driving instruction from the camera 58, thelens CPU 57 switches the driving signals for the phases A, B to thevibrating type motor 22 to the phase difference for generating travelingwave vibration in order to perform the next driving of the focus lens19.

In the embodiment, the vibrating type motor 22 is caused to vibrate in astanding wave each time the focus lens 19 is temporarily stopped afterdriving during the focus operation until focusing is achieved in theoperation of the contrast detection scheme AF. Alternatively, it ispossible that a time period until the focus lens 19 is moved to within apredetermined range (near the in-focus position) including the in-focusposition is set as a first mode, a time period until the focus lens 19is moved to the in-focus position in that predetermined range is set asa second mode, and the vibrating type motor 22 is caused to generate thestanding wave vibration and not to be driven only at the time oftemporary stop when the focus lens 19 is repeatedly driven by a smallamount in the second mode.

In the respective embodiments described above, since the vibrating typemotors 15, 22 vibrate in a standing wave so as not to drive the motors15, 22 and the focus lenses 2, 19 during the temporary stop of the focuslenses 2, 19 while the contrast detection scheme AF is performed, thevibrating type motor 22 can be quickly actuated at the time of the nextdriving by a certain amount. Thus, it is possible to reduce a time takenfor achieving focus. In addition, since the vibrating type motors 15, 22are made non-vibrating to completely stop the driving when focus isachieved, the focus lenses 2, 19 can be fixed to hold the in-focusstate.

While the respective embodiments described above have been described forthe digital still camera of the type containing the image-taking lensand a combination of the digital still camera or the film camera and theinterchangeable lens apparatus, the present invention is applicable to avideo camera or a combination of a video camera and an interchangeablelens.

As described above, in the embodiments shown in FIGS. 1 to 7, since thestator of the vibrating type motor is not non-vibrating but vibrating ina standing wave during the stop of the focus lens in the focus operationin which the focus lens is repeatedly driven and stopped, the vibratingtype motor can be actuated in a shorter time than is required forstarting to actuate the vibrating type motor (that is, the focus lens)by switching the stator to traveling wave vibration from a non-vibratingstate. Thus, in the contrast detection scheme or the contrast scheme AFwhich requires repeated driving and stop of the focus lens at highspeed, the startup properties and drive-following properties of thefocus lens can be improved to reduce time taken for achieving finalfocusing.

FIG. 8 is a block diagram showing the configuration of a digital camerawhich contains an image-taking lens as an integral part and is anotherembodiment of the present invention. In FIG. 8, reference numeral 101shows the digital camera (hereinafter simply referred to as a camera) Inan image-taking optical system, reference numeral 102 shows a focus lenswhich performs focus adjustment, 103 a zoom lens which adjusts amagnification, 104 a stop which adjusts an amount of light. Referencenumeral 106 shows an image pickup device such as a CCD and CMOS whichphotoelectrically converts image light to an image signal for output,and 105 a shutter which adjusts an amount of light to the image pickupdevice 106.

Reference numeral 107 shows an A/D converter which digitizes an imagesignal from the image pickup device 106, 108 an electrical viewfindersystem which displays an image picked up by the image pickup device 106,109 a digital signal processing section which performs various digitalsignal processing of a digital image signal converted by the A/Dconverter 107, 110 a buffer memory used to temporarily store the digitalimage signal or the like, and 111 a recording medium such as a flashmemory or other semiconductor memory, magnetic disk, optical disk, etc.which records taken digital data.

Reference numeral 112 shows an external LCD display system whichdisplays various image-taking information, and 113 a camera CPUresponsible for various controls in the camera, 114 a stop drivingmotor, 115 a vibrating type motor which drives the focus lens 102, 116 adriver circuit which drives the vibrating type motor 115, and 117 adriver circuit which drives the stop driving motor 114. The camera 101is equipped with a power source, although not shown. The image pickupdevice 106 and the camera CPU 113 constitute a second focus detectionunit. The configuration and the operation of the vibrating type motor115 are similar to those of the vibrating type motor described in theaforementioned respective embodiments.

Reference numeral 150 shows a mirror unit and comprises a main mirrorand a sub-mirror similarly to that shown in FIG. 12. Each of the mainmirror and sub-mirror is formed of a half-mirror. Reference numeral 151shows a phase difference scheme focus detection unit (a first focusdetection unit) and comprises a secondary imaging optical system and anAF sensor similarly to that shown in FIG. 12.

Next, description is made for the focus adjusting operation in thecamera 101 (mainly of the camera CPU 113) of the embodiment withreference to a flow chart of FIG. 9(A) and FIG. 9(B). Lines addedcircled 2 in FIG. 9(A) and FIG. 9(B) are connected to each other.

[Step 501]

When a power switch, not shown, is turned ON, power is supplied to thecamera CPU 113 and this processing is started.

[Step 502]

The camera CPU 113 determines whether or not a release button, notshown, provided for the camera 101 is half-pressed to turn animage-taking preparation switch SW1 ON. The sequence proceeds to step503 if it is turned on, or the camera CPU 113 enters a standby state ifit is OFF.

[Step 503]

The camera CPU 113 calculates “an amount of correlation” in the phasedifference scheme AF based on output from the phase difference schemefocus adjustment unit 151 to perform first-stage driving control (thatis, focusing control) for achieving focusing in the vibrating type motor115.

[Step 504]

The camera CPU 113 calculates a defocus amount of the image-taking lensbased on the correlation amount calculated at step 503 and optical datasuch as focus sensitivity of the image-taking lens.

[Step 505]

The camera CPU 113 controls the driver circuit 116 to drive thevibrating type motor 115 for acceleration and deceleration based on thedefocus amount calculated at step 504. The driving of the vibrating typemotor 115 is stopped at the time when the movement of the focus lens 102by a predetermined amount is detected from output from an encoder (notshown). The first-stage focusing control with rough positionalresolution is then ended.

[Step 506]

The camera CPU 113 proceeds to intermediate control for generatingstanding wave vibration on the stator of the vibrating type motor 115immediately after the completion of the first-stage focusing control atstep 505. Higher frequency components are extracted from an image signaloutput from the image pickup device 106 for performing second-stagefocusing control as below.

The standing wave can be generated by applying a driving signal to oneof the electrodes A1, B1 shown in FIG. 16 or applying driving signalswith the same phases to the electrodes A1, B1. Driving signals with aphase difference of 180 degrees may be applied to the electrodes A1, B1.

The standing wave vibration generated on the stator in this mannercauses the rotor (driven member) to be in a floating state to thestator. Consequently, startup properties are improved when the stator isnext caused to vibrate in a traveling wave to actuate the rotor (thatis, the focus lens 102).

[Step 507]

The camera CPU 113 drives the focus lens 102 by a certain amount toperform the second-stage focusing control with fine resolution. In thisevent, the driving amount may be always constant or may be changed inaccordance with the newest value of the higher frequency component data.For example, when the value of the higher frequency component dataextracted at step 506 is small, the focus lens 102 is considered asbeing at some distance from an in-focus position and the driving amountis increased, and when the value of the higher frequency component datais large, the focus lens 102 is considered as being near the in-focusposition and the driving amount is reduced.

During the transition from step 506 to 507, the vibrating type motor 115is not driven while the stator is vibrating (in a standing wave) by theaforementioned intermediate control. Thus, at step 507, high frequencydriving signals are applied to the stator of the vibrating type motor115 to form a traveling wave, and the vibrating type motor 115 isactuated with the frequency being gradually reduced.

In this event, the phase difference between the phase A and phase Sdescribed above is read to perform control such that the drivingfrequency does not fall below the resonance frequency f0.

The traveling wave can be generated by applying driving signals with aphase difference of 90 degrees to the electrode A1 and the electrode B1shown in FIG. 16. The driving direction may be switched by advancing ordelaying the phase of the signal applied to the electrode B1 withrespect to the signal applied to the electrode A1.

After the driving by the certain amount, the driving signal to thevibrating type motor 115 is switched from one for generating a travelingwave to one for generating a standing wave to cause the stator togenerate standing wave vibration, and the focus lens 102 is temporarilystopped. The driving frequency when the traveling wave vibration isswitched to the standing wave vibration is a startup frequency (theaforementioned high frequency) used for starting to actuate thevibrating type motor 115 by the traveling wave vibration.

[Step 508]

The camera CPU 113 causes the digital signal processing section 109 toacquire the image signal from the image pickup device 106.

[Step 509]

The camera CPU 113 extracts higher frequency components from the imagesignal acquired by the digital signal processing section 109 at step508.

[Step 510]

The camera CPU 113 compares the previously extracted higher frequencycomponent data with the higher frequency component data extracted thistime. If the previously extracted data shows a larger value, thein-focus position is determined as being opposite to the current movingdirection of the focus lens 102 and the sequence proceeds to step 511,or otherwise, the in-focus position is determined as matching thecurrent moving direction of the focus lens 102 and the sequence proceedsto step 512. Up to this point, the vibrating type motor 115 is driven tovibrate in a standing wave.

[Step 511]

The camera CPU 113 makes setting to reverse the next driving directionof the focus lens 102 to the current driving direction.

[Step 512]

The camera CPU 113 temporarily stores the higher frequency componentdata extracted at step 509 in the buffer memory 110.

[Step 513]

The camera CPU 113 determines whether or not focusing (in-focus state)is achieved from the stored value of the higher frequency componentdata, the condition whether the focus lens 102 is reversely driven nearthe current position of the focus lens 102, and the like.

When it is determined that focus is achieved, the sequence proceeds tostep 514, or when it is determined that focusing is not achieved, thesequence returns to step 507 and the next driving of the focus lens 102is performed. Specifically, the vibrating type motor 115 is switchedfrom the standing wave driving to the traveling wave driving and isdriven by the certain amount.

[Step 514]

The camera CPU 113 stops the driving of the focus lens 102 sincefocusing is achieved at step 513. In this event, the vibrating typemotor 115 vibrating in a standing wave is completely stopped byterminating the application of the driving signal.

This is performed for the following reason. Since the rotor of thevibrating type motor is floating to the stator in the standing wavevibration, and the focus lens 102 is readily moved by a small externalforce and the in-focus position cannot be maintained, the standing wavevibration is stopped to produce friction force from press contact of thestator with the rotor, thereby maintaining the in-focus position. Inaddition, the stop of the standing wave vibration has the effect ofpower savings.

As described above, according to the embodiment, the vibrating typemotor 115 is caused to vibrate in a standing wave by the intermediatecontrol from the end of the first-stage driving control of the vibratingtype motor 115, that is, the focusing control of the focus lens 102based on the detection result of the focus adjustment state in the phasedifference detection scheme until the start of the second-stage drivingcontrol, that is, the focusing control of the focus lens 102 based onthe detection result of the focus adjustment state in the contrastdetection scheme. Thus, driving of the focus lens 102 can be quicklystarted in the second-stage driving control.

In addition, since the vibrating type motor 115 is also caused tovibrate in a standing wave during the temporary stop of the focus lens102 while higher frequency components are extracted and focusdetermination is made after the driving of the focus lens 102 by thecertain amount in the second-stage driving control, the next driving ofthe focus lens 102 by the certain amount can be quickly started. Thus,focusing can be achieved more accurately in a shorter time than in theconventional hybrid scheme AF.

FIG. 10 is a block diagram showing the configuration of a camera systemwhich is another embodiment of the present invention and comprises adigital camera (hereinafter simply referred to as a camera) and aninterchangeable lens removably mounted on the camera.

In FIG. 10, reference numeral 118 shows the interchangeable lens. In animage-taking optical system of the interchangeable lens 118, referencenumeral 119 shows a focus lens which performs focus adjustment, 120 azoom lens which adjusts a magnification, and 121 a stop which adjusts anamount of light.

Reference numeral 122 shows a vibrating type motor which drives thefocus lens 119, 123 a stop driving motor, 124 a driver circuit whichdrives the vibrating type motor 122, 125 a driver circuit which drivesthe stop driving motor 123, 126 and 138 communication circuits whichperform communication of data or the like with the camera, and 127 alens CPU responsible for control in the interchangeable lens 18.

On the other hand, reference numeral 128 shows the digital camera, 129an electrical viewfinder system, 131 an image pickup device such as aCCD and a CMOS which photoelectrically converts image light to an imagesignal for output, 130 a shutter which adjusts an amount of lightreaching the image pickup device 131, 132 an A/D converter whichdigitizes an image signal from the image pickup device 131, 133 adigital signal processing section which performs various digital signalprocessing of a digital image signal converted by the A/D converter 132,and 134 a buffer memory used to temporarily store the digital imagesignal or the like.

Reference numeral 135 shows a recording medium such as a flash memory orother semiconductor memory, magnetic disk, optical disk, etc. whichrecords taken digital data, 136 an external LCD display system whichdisplays various image-taking information, 137 a camera CPU responsiblefor control in the camera, and 138 a communication circuit whichperforms communication of data or the like with the interchangeable lens118. The camera 128 is equipped with a power source, although not shown,and the interchangeable lens 118 is also supplied with power from thepower source. The image pickup device 131 and the camera CPU 137constitute a second focus detection unit.

Reference numeral 160 shows a mirror unit and comprises a main mirrorand a sub-mirror similarly to that shown in FIG. 12. Each of the mainmirror and sub-mirror is formed of a half-mirror. Reference numeral 161shows a phase difference scheme focus detection unit (a first focusdetection unit) and comprises a secondary imaging optical system and anAF sensor similarly to that shown in FIG. 12.

The configuration and the operation of the vibrating type motor 122 aresimilar to those of the vibrating type motor described in theaforementioned respective embodiments.

Next, the focus adjusting operation of the camera system (mainly of thecamera CPU 137 and the lens CPU 127) of the embodiment is described withreference to a flow chart of FIG. 11(A) and FIG. 11(B). Lines addedcircled 3 in FIG. 11(A) and FIG. 11(B) are connected to each other.

[Step 601]

The camera CPU 137 starts processing in response to turn-on of a powerswitch, not shown, provided for the camera 128.

[Step 602]

The camera CPU 137 determines whether or not a release button, notshown, provided for the camera 128 is half-pressed to turn animage-taking preparation switch SW1 ON. The sequence proceeds to step603 if it is turned on, or the camera CPU 137 enters a standby state ifit is OFF.

[Step 603]

The camera CPU 137 calculates “an amount of correlation” in the phasedifference scheme AF based on output from the phase difference schemefocus adjustment unit 161 to perform first-stage driving control (thatis, focusing control) for achieving focusing in the vibrating type motor122.

[Step 604]

The camera CPU 137 calculates a defocus amount of the image-taking lensbased on the correlation amount calculated at step 603 and optical datasuch as focus sensitivity of the image-taking lens previouslytransmitted from the lens CPU 127 through the communication circuits126, 138.

[Step 605]

The camera CPU 137 communicates a lens driving instruction to the lensCPU 127 through the communication circuits 138, 126. The lens CPU 127drives the vibrating type motor 122 for acceleration and decelerationthrough the driver circuit 124. Output from an encoder (not shown)provided in the interchangeable lens 118 is transmitted to the cameraCPU 137 from the lens CPU 127 through the communication circuits 126,138. At the time when the camera CPU 137 detects that the focus lens 119is moved by a predetermined amount corresponding to the aforementioneddefocus amount, the camera CPU 137 transmits a lens driving stopinstruction to the lens CPU 127 to stop the driving of the vibratingtype motor 122, thereby ending the first-stage focusing control withrough position resolution.

[Step 606]

The camera CPU 137 transmits a standing wave driving instruction to thelens CPU 127 immediately after the completion of the first-stagefocusing control. The lens CPU 127 proceeds to intermediate control forgenerating standing wave vibration on the stator of the vibrating typemotor 122 through the driver circuit 124. At this time, the camera CPU137 extracts higher frequency components from an image signal outputfrom the image pickup device 131 in order to perform second-stagefocusing control.

The standing wave can be generated by applying a driving signal to oneof the electrodes A1, B1 shown in FIG. 16 or applying driving signalswith the same phases to the electrodes A1, B1. Driving signals with aphase difference of 180 degrees may be applied to the electrodes A1, B1.

The standing wave vibration generated on the stator in this mannercauses the rotor to be in a floating state to the stator. Consequently,startup properties are improved when the stator is next caused tovibrate in a traveling wave to actuate the rotor (that is, the focuslens 119).

[Step 607]

The camera CPU 137 transmits a certain amount driving instruction to thelens CPU 127. The lens CPU 127 causes traveling wave vibration to begenerated on the stator of the vibrating type motor 122 through thedriver circuit 124 to drive the focus lens 119 by a certain amount.

In this event, the driving amount may be always constant or may bechanged in accordance with the newest value of the higher frequencycomponent data. For example, when the value of the higher frequencycomponent data extracted at step 606 is small, the focus lens 119 isconsidered as being at some distance from an in-focus position and thedriving amount is increased, and when the value of the higher frequencycomponent data is large, the focus lens 119 is considered as being nearthe in-focus position and the driving amount is reduced.

During the transition from step 606 to 607, the vibrating type motor 122is not driven while the stator is vibrating (in a standing wave) by theaforementioned intermediate control. Thus, at step 607, high frequencydriving signals are applied to the stator of the vibrating type motor122 to form a traveling wave, and the vibrating type motor 122 isactuated with the frequency being gradually reduced.

In this event, the phase difference between the phase A and phase Sdescribed above is read to perform control such that the drivingfrequency does not fall below the resonance frequency f0.

The traveling wave can be generated by applying driving signals with aphase difference of 90 degrees to the electrode A1 and the electrode B1shown in FIG. 16. The driving direction may be switched by advancing ordelaying the phase of the signal applied to the electrode B1 withrespect to the signal applied to the electrode A1.

After the driving by the certain amount, the driving signal to thevibrating type motor 122 is switched from one for generating a travelingwave to one for generating a standing wave to generate standing wavevibration on the stator, and the focus lens 119 is temporarily stopped.

[Step 608]

The camera CPU 137 causes the digital signal processing section 133 toacquire the image signal from the image pickup device 131.

[Step 609]

The camera CPU 137 extracts higher frequency components from the imagesignal acquired by the digital signal processing section 133 at step608.

[Step 610]

The camera CPU 137 compares the previously extracted higher frequencycomponent data with the higher frequency components extracted this time.If the previously extracted data shows a larger value, the in-focusposition is determined as being opposite to the current moving directionof the focus lens 119 and the sequence proceeds to step 611, orotherwise, the in-focus position is determined as matching the currentmoving direction of the focus lens 119 and the sequence proceeds to step612.

[Step 611]

The camera CPU 137 makes setting to reverse the next driving directionof the focus lens 119 to the current driving direction.

[Step 612]

The camera CPU 113 temporarily stores the data on the higher frequencycomponents extracted at step 609 in the buffer memory 134.

[Step 613]

The camera CPU 137 determines whether or not focusing (in-focus state)is achieved from the stored value of the higher frequency componentdata, the condition whether the focus lens 119 is reversely driven nearthe current position of the focus lens 119, and the like.

When it is determined that focusing is achieved, the sequence proceedsto step 614, or when it is determined that focusing is not achieved, thesequence returns to step 607 and the next driving of the focus lens 119is performed.

[Step 614]

Since focusing is achieved at step 613, the camera CPU 137 stops thedriving of the focus lens 119. In this event, the vibrating type motor122 vibrating in a standing wave is completely stopped by terminatingthe application of the driving signal. This is performed for thefollowing reason. Since the rotor of the vibrating type motor isfloating to the stator in the standing wave vibration, and the focuslens 119 is readily moved by a small external force and the in-focusposition cannot be maintained, the standing wave vibration is stopped toproduce friction force from press contact of the stator with the rotor,thereby maintaining the in-focus position. In addition, the stop of thestanding wave vibration has the effect of power savings.

As described above, according to the embodiment, the vibrating typemotor 122 is caused to vibrate in a standing wave by the intermediatecontrol from the end of the first-stage driving control of the vibratingtype motor 122, that is, the focusing control of the focus lens 119based on the detection result of the focus adjustment state in the phasedifference detection scheme until the start of the second-stage drivingcontrol, that is, the focusing control of the focus lens 119 based onthe detection result of the focus adjustment state in the contrastdetection scheme. Thus, driving of the focus lens 119 can be quicklystarted in the second-stage driving control.

In addition, since the vibrating type motor 122 is also caused tovibrate in a standing wave during the temporary stop of the focus lens119 while higher frequency components are extracted and focusdetermination is made after the driving of the focus lens 119 by thecertain amount in the second-stage driving control, the next driving ofthe focus lens 119 by the certain amount can be quickly started. Thus,focusing can be achieved more accurately in a shorter time than in theconventional hybrid scheme AF.

While the AF sensor used in the phase difference detection scheme AF isprovided below the mirror unit 150, 160 in the aforementionedembodiments, the present invention is not limited to such aconfiguration. The present invention may have a configuration having theAF sensor arranged on an imaging surface of a secondary imaging opticalsystem additionally provided above the mirror unit.

As described above, according to the respective embodiments shown inFIGS. 8 to 11, the stator of the vibrating type motor is caused togenerate standing wave veneration from the end of the first-stagedriving control of the vibrating type motor (the driving of the focuslens based on the detection result of the focus adjustment state in thephase difference detection scheme) performed by driving the focus lensfor achieving focusing until the start of the second-stage drivingcontrol (the driving of the focus lens based on the detection result ofthe focus adjustment state in the contrast detection scheme). Thus,driving of the focus lens in the image-taking system can be quicklystarted in the second-stage driving control, and focus can be achievedmore accurately in a shorter time than in the conventional hybrid schemeAF.

While preferred embodiments have been described, it is to be understoodthat modification and variation of the present invention may be madewithout departing from the sprit or scope of the following claims.

1. A lens apparatus having an image-taking optical system which forms anoptical image by luminous flux from a subject and includes a focus lens,and a vibrating type motor which drives said focus lens, said vibratingtype motor including a vibrating member, an electro-mechanical energyconversion element which excites vibration on said vibrating member, anda driven member driven by the vibration of said vibrating member, saidlens apparatus being removably mounted on a camera, said camera havingan image pickup device which photoelectrically converts said opticalimage to an image signal and outputs the image signal, said cameraextracting higher frequency components from the image signal obtainedfrom said image pickup device in each stopped state of said focus lensand outputting a command signal for performing focus adjusting operationin accordance with a determination result of a focus adjustment state ofsaid image-taking optical system determined on the basis of said higherfrequency components, said lens apparatus comprising: a communicationcircuit which transmits and receives a signal to and from said camera;and a control circuit which controls said vibrating type motor torepeatedly drive and stop said focus lens and performs focus adjustingoperation of moving said focus lens to an in-focus position in responseto the command signal received from said camera through saidcommunication circuit, wherein said control circuit causes travelingwave vibration to be generated on the vibrating member of said vibratingtype motor when said focus lens is driven and causes standing wavevibration to be generated on said vibrating member while said focus lensis stopped during said focus adjusting operation, wherein said controlcircuit has a first mode for driving said focus lens to near thein-focus position and a second mode for driving said focus lens fromnear the in-focus position to the in-focus position, and said controlcircuit causes traveling wave vibration to be generated on the vibratingmember of said vibrating type motor when said focus lens is driven andcauses standing wave vibration to be generated on said vibrating memberwhile said focus lens is stopped only in said second mode.
 2. A camerasystem including a lens apparatus, said lens apparatus having animage-taking optical system which forms an optical image by luminousflux from a subject and includes a focus lens, and a vibrating typemotor which drives said focus lens, said vibrating type motor includinga vibrating member, an electro-mechanical energy conversion elementwhich excites vibration on said vibrating member, and a driven memberdriven by the vibration of said vibrating member, and a camera on whichsaid lens apparatus is removably mounted, said camera having an imagepickup device which photoelectrically converts said optical image to animage signal and outputs the image signal, said camera extracting higherfrequency components from the image signal obtained from said imagepickup device in each stopped state of said focus lens and outputting acommand signal for performing focus adjusting operation in accordancewith a focus adjustment state of said image-taking optical systemdetermined on the basis of said higher frequency components, said camerasystem comprising: a communication circuit which transmits and receivesa signal between said lens apparatus and said camera; and a controlcircuit provided for said lens apparatus which controls said vibratingtype motor to repeatedly drive and stop said focus lens and performsfocus adjusting operation of moving said focus lens to an in-focusposition in response to the command signal received from said camerathrough said communication circuit, wherein said control circuit causestraveling wave vibration to be generated on the vibrating member of saidvibrating type motor when said focus lens is driven and causes standingwave vibration to be generated on said vibrating member while said focuslens is stopped during said focus adjusting operation, wherein saidcontrol circuit determines whether or not said camera supports a focusadjustment method in which higher frequency components are extractedfrom the image signal obtained by said image pickup device in eachstopped state of said focus lens and focus adjusting operation for saidfocus lens is performed in accordance with a determination result of afocus adjustment state of said image-taking optical system based on saidhigher frequency components, and when it is determined that said camerasupports said focus adjustment method, said control circuit causestraveling wave vibration to be generated on the vibrating member of saidvibrating type motor when said focus lens is driven and causes standingwave vibration to be generated on said vibrating member while said focuslens is stopped during said focus adjusting operation.
 3. A camerasystem including a lens apparatus, said lens apparatus having animage-taking optical system which forms an optical image by luminousflux from a subject and includes a focus lens, and a vibrating typemotor which drives said focus lens, said vibrating type motor includinga vibrating member, an electro-mechanical energy conversion elementwhich excites vibration on said vibrating member, and a driven memberdriven by the vibration of said vibrating member, and a camera on whichsaid lens apparatus is removably mounted, said camera having an imagepickup device which photoelectrically converts said optical image to animage signal and outputs the image signal, said camera extracting higherfrequency components from the image signal obtained from said imagepickup device in each stopped state of said focus lens and outputting acommand signal for performing focus adjusting operation in accordancewith a focus adjustment state of said image-taking optical systemdetermined on the basis of said higher frequency components, said camerasystem comprising: a communication circuit which transmits and receivesa signal between said lens apparatus and said camera; and a controlcircuit provided for said lens apparatus which controls said vibratingtype motor to repeatedly drive and stop said focus lens and performsfocus adjusting operation of moving said focus lens to an in-focusposition in response to the command signal received from said camerathrough said communication circuit, wherein said control circuit causestraveling wave vibration to be generated on the vibrating member of saidvibrating type motor when said focus lens is driven and causes standingwave vibration to be generated on said vibrating member while said focuslens is stopped during said focus adjusting operation, wherein saidcontrol circuit has a first mode for driving said focus lens to near thein-focus position and a second mode for driving said focus lens fromnear the in-focus position to the in-focus position, and said controlcircuit causes traveling wave vibration to be generated on the vibratingmember of said vibrating type motor when said focus lens is driven andcauses standing wave vibration to be generated on said vibrating memberwhile said focus lens is stopped only in said second mode.
 4. A cameracomprising: an image-taking optical system which forms an optical imageby luminous flux from a subject and includes a focus lens; a first focusdetection unit which detects a focus adjustment state of saidimage-taking optical system in a phase difference detection method byusing luminous flux from said image-taking optical system; an imagepickup device which photoelectrically converts the optical image formedby said image-taking optical system to an image signal and outputs theimage signal; a second focus detection unit which detects a focusadjustment state of said image-taking optical system in a contrastdetection method based on the image signal from said image pickupdevice; a vibrating type motor which drives said focus lens, saidvibrating type motor including a vibrating member, an electro-mechanicalenergy conversion element which excites vibration on said vibratingmember, and a driven member driven by the vibration of said vibratingmember; and a control circuit which controls said vibrating type motorbased on the detection results of said first and second focus detectionunits, wherein said control circuit performs first-stage driving controlfor generating traveling wave vibration on the vibrating member of saidvibrating type motor based on the detection result of said first focusdetection unit, then performs second-stage driving control forgenerating traveling wave vibration on said vibrating member based onthe detection result of said second focus detection unit, and performsintermediate control for generating standing wave vibration on saidvibrating member from after completion of said first-stage drivingcontrol until start of said second-stage driving control.
 5. The cameraaccording to claim 4, wherein said focus lens is moved with higherposition resolution in said second-stage driving control than positionresolution of said focus lens in said first-stage driving control. 6.The camera according to claim 4, wherein the traveling wave vibration isgenerated on said vibrating member by applying driving signals with aphase difference to a phase A and a phase B of said electro-mechanicalenergy conversion element in said vibrating type motor, and the standingwave vibration is generated on said vibrating member by applying adriving signal to only one of said phase A and said phase B in saidintermediate control.
 7. The camera according to claim 4, wherein thetraveling wave vibration is generated on said vibrating member byapplying driving signals with a phase difference to a phase A and aphase B of said electro-mechanical energy conversion element in saidvibrating type motor, and the standing wave vibration is generated onsaid vibrating member by applying driving signals with the same phasesto said phase A and said phase B in said intermediate control.
 8. Thecamera according to claim 4, wherein the traveling wave vibration isgenerated on said vibrating member by applying driving signals with aphase difference other than 180 degrees to a phase A and a phase B ofsaid electro-mechanical energy conversion element in said vibrating typemotor, and the standing wave vibration is generated on said vibratingmember by applying driving signals with a phase difference of 180degrees to said phase A and said phase B in said intermediate control.9. The camera according to claim 4, wherein said control circuitperforms control to generate the standing wave vibration on saidvibrating member when said vibrating type motor is temporarily stoppedduring said second-stage driving control.
 10. A lens apparatus having animage-taking optical system which forms an optical image by luminousflux from a subject and includes a focus lens, and a vibrating typemotor which drives said focus lens, said vibrating type motor includinga vibrating member, an electro-mechanical energy conversion elementwhich excites vibration on said vibrating member, and a driven memberdriven by the vibration of said vibrating member, said lens apparatusbeing removably mounted on a camera, said camera having a first focusdetection unit which detects a focus adjustment state of saidimage-taking optical system in a phase difference detection method byusing luminous flux from said image-taking optical system, an imagepickup device which photoelectrically converts the optical image formedby said image-taking optical system to an image signal and outputs theimage signal, and a second focus detection unit which detects a focusadjustment state of said image-taking optical system in a contrastdetection method based on the image signal from said image pickupdevice, and said camera outputting a command signal for performing focusadjusting operation based on signals from said first and second focusdetection units, said lens apparatus comprising: a communication circuitwhich transmits and receives a signal to and from said camera; and acontrol circuit which controls said vibrating type motor in response tothe command signal received from said camera through said communicationcircuit, wherein said control circuit performs first-stage drivingcontrol for generating traveling wave vibration on the vibrating memberof said vibrating type motor based on the detection result of said firstfocus detection unit, then performs second-stage driving control forgenerating traveling wave vibration on said vibrating member based onthe detection result of said second focus detection unit, and performsintermediate control for generating standing wave vibration on saidvibrating member from after completion of said first-stage drivingcontrol until start of said second-stage driving control.
 11. The lensapparatus according to claim 10, wherein said focus lens is moved withhigher position resolution in said second-stage driving control thanposition resolution of said focus lens in said first-stage drivingcontrol.
 12. The lens apparatus according to claim 10, wherein thetraveling wave vibration is generated on said vibrating member byapplying driving signals with a phase difference to a phase A and aphase B of said electro-mechanical energy conversion element in saidvibrating type motor, and the standing wave vibration is generated onsaid vibrating member by applying a driving signal to only one of saidphase A and said phase B in said intermediate control.
 13. The lensapparatus according to claim 10, wherein the traveling wave vibration isgenerated on said vibrating member by applying driving signals with aphase difference to a phase A and a phase B of said electro-mechanicalenergy conversion element in said vibrating type motor, and the standingwave vibration is generated on said vibrating member by applying drivingsignals with the same phases to said phase A and said phase B in saidintermediate control.
 14. The lens apparatus according to claim 10,wherein the traveling wave vibration is generated on said vibratingmember by applying driving signals with a phase difference other than180 degrees to a phase A and a phase B of said electro-mechanical energyconversion element in said vibrating type motor, and the standing wavevibration is generated on said vibrating member by applying drivingsignals with a phase difference of 180 degrees to said phase A and saidphase B in said intermediate control.
 15. The lens apparatus accordingto claim 10, wherein said control circuit performs control to generatethe standing wave vibration on said vibrating member when said vibratingtype motor is temporarily stopped during said second-stage drivingcontrol.
 16. A camera system including a lens apparatus, said lensapparatus having an image-taking optical system which forms an opticalimage by luminous flux from a subject and includes a focus lens, and avibrating type motor which drives said focus lens, said vibrating typemotor including a vibrating member, an electro-mechanical energyconversion element which excites vibration on said vibrating member, anda driven member driven by the vibration of said vibrating member, and acamera having a first focus detection unit which detects a focusadjustment state of said image-taking optical system in a phasedifference detection method by using luminous flux from saidimage-taking optical system, an image pickup device whichphotoelectrically converts the optical image formed by said image-takingoptical system to an image signal and outputs the image signal, and asecond focus detection unit which detects a focus adjustment state ofsaid image-taking optical system in a contrast detection method based onthe image signal from said image pickup device, and said cameraoutputting a command signal for performing focus adjusting operationbased on signals from said first and second focus detection units, saidcamera system comprising: a communication circuit which transmits andreceives a signal between said camera and said lens apparatus; and acontrol circuit provided for said lens apparatus which controls saidvibrating type motor in response to the command signal received throughsaid communication circuit, wherein said control circuit performsfirst-stage driving control for generating traveling wave vibration onthe vibrating member of said vibrating type motor based on the detectionresult of said first focus detection unit, then performs second-stagedriving control for generating traveling wave vibration on saidvibrating member based on the detection result of said second focusdetection unit, and performs intermediate control for generatingstanding wave vibration on said vibrating member from after completionof said first-stage driving control until start of said second-stagedriving control.
 17. The camera system according to claim 16, whereinsaid focus lens is moved with higher position resolution in saidsecond-stage driving control than position resolution of said focus lensin said first-stage driving control.
 18. The camera system according toclaim 16, wherein the traveling wave vibration is generated on saidvibrating member by applying driving signals with a phase difference toa phase A and a phase B of said electro-mechanical energy conversionelement in said vibrating type motor, and the standing wave vibration isgenerated on said vibrating member by applying a driving signal to onlyone of said phase A and said phase B in said intermediate control. 19.The camera system according to claim 16, wherein the traveling wavevibration is generated on said vibrating member by applying drivingsignals with a phase difference to a phase A and a phase B of saidelectro-mechanical energy conversion element in said vibrating typemotor, and the standing wave vibration is generated on said vibratingmember by applying driving signals with the same phases to said phase Aand said phase B in said intermediate control.
 20. The camera systemaccording to claim 16, wherein the traveling wave vibration is generatedon said vibrating member by applying driving signals with a phasedifference other than 180 degrees to a phase A and a phase B of saidelectro-mechanical energy conversion element in said vibrating typemotor, and the standing wave vibration is generated on said vibratingmember by applying driving signals with a phase difference of 180degrees to said phase A and said phase B in said intermediate control.21. The camera system according to claim 16, wherein said controlcircuit performs control to generate the standing wave vibration on saidvibrating member when said vibrating type motor is temporarily stoppedduring said second-stage driving control.